1984. Importance to mussels of the benthic boundary layer. Can. 1. Fish. Aquat. Sci. 41 : 1618-1625 We examined whether populations of the blue mussel Mytiius edulbs (Linnaeus, 1758) and horse mussel Modiolus modiolus (Linnaeus, 1758) could, by their feeding activities, deplete the sestonic food supply. The experiments were conducted in a 5-m-long by 56-cm-wide flume in which a turbulent boundary layer flow was created. The seston concentration was measured both as AT$ content and numbers of bacteria by acridline orange staining technique on separate subsamples of seawater. Sampling locations were at the flume inlet and at a point 3.6 m downstream (outlet). Four of the five replicated experiments with blue mussels had significant AHP-seston depletion but no reduction in bacterial numbers at the outlet sampling location. Of three replicated experiments with horse mussels, two had significant ATP-seston depletion and all three had significantly fewer bacterial numbers at the outlet sampling location. We consider that these results provide direct evidence in support of the hypothesis that seawater hydrodynamic factors may be critical in determining the food supply available to suspension-feeding animals. Our results confirm circurnstantia% evidence on this point obtained from field observations by previous investigators. Experimental verification of seston depletion is a necessary, but not sufficient, step in establishing that suspension-feeding animals may be food limited as required by the trophic group mutual exclusion hypothesis.Nous avons tent6 de determiner si les populations de moules bleues, Myfilus edudis (Linnaeus, 1758), et de rnodioles, Modiolus msdisius (Linnaeus, 1758), pouvaient, en se nourrisant, epuiser la rkserve de seston. Les experiences ont ete realisees dans uneenceinte de5 m dle long et56 cm de large dans lequel on a cree un courant turbulent de couche limitrophe. La concentration du seston dans differents 6chantilions d'eau de mer a kt6 6valuee en mesurant la teneur en A-BP et le nombre de bacterie au rnoyen d'une coloration a ['orange d'acridine. Les echantillons ont ete prelev6s a %'entree de Ifenceinte et A un point situCI h 3,6 rn en aval (sortie). Dans quatre des cinq essais realises avec les moules bleues, %a teneur du seston en ATP au point de prelevement situe era aval avait serieusement diminue, contrairernent au nombre de bacteries qui etait rest6 le meme. Dans deux des trois essais realises avec les rnodioles, on a obtenu une teneur en ATP nettement dirninuke, et dans les trois cas, le nombre de bacteries a la sortie de Ifenceinte etait beaucoup plus faible. Nous considerons que ces r6sultats appuient directement Ifhypothese selon laquelle la reserve de nourriture accessible aux anirnaux se nourrissant d'elernents en suspension est determinee de facon critique par des facteurs hydrodynamiques de I'eau de mer. Nos resultats confirment les suppositions circonstanciees formulees anterieurement a partir d'observations in situ par d'autres chercheurs. La verification experimentale est ...

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A quantitative hypothesis is presented that current velocity and roughness at the sediment–water interface control the numbers, biomass, and growth of suspension-feeding macrobenthic animals. The controls are the effect of tidal currents on turbulent mass transfer of food to suspension-feeding animals and direct inhibition of growth and settlement by currents in excess of 12–30 cm/s. The rate of turbulent supply of ATP associated with seston is proposed as a practical way of determining growth potentials of suspension-feeding macrobenthos at current velocities less than 30 cm/s. Key words: sublittoral macrobenthos, tidal velocity, potential population growth, Bay of Fundy estuaries

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Growth experiments confirm that production by a bed of blue mussels (Mytilus edulis) may be controlled by tidal current speed through its effect on seston supply. The mechanism of this effect involves a downstream seston depletion and is thus applicable only to populations of mussels. Individual physiological responses by mussels, such as increased filtration, ingestion and assimilation rates at higher current speeds, are not involved in the enhanced bivalve production observed.

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(1) have recently reported a successful prediction of vapor-liquid equilibria in binaries of acetates and alcohols using a theory of liquid mixtures developed by Barker ( 2 , 3 ) . In this treatment the liquid is assumed to have a quasicrystalline structure in which there is short-range order and long-range disorder. The molecules are assumed to occupy well-defined sites on a regular lattice and the interactions of the molecules with their neighbors are considered. The interaction energies are assumed to depend upon the nature of the molecular surfaces which are adjacent to each other and if suitable values are assigned to these energy terms, it is possible to calculate the excess chemical potential of the mixture and the activity coefficients. Sweeney and Rose showed that for the homologous set of binary mixtures of normal alcohols and their acetates ( CnH2n t 10H and CnHsn + 1COOCH3) a single set of interaction energies, obtained by fitting to data for one member of the set, can be used to predict vapor-liquid equilibria for the others.In this way Sweeney and Rose showed that the same interaction energies satisfactorily correlated C1, Cz, Cq, and Cs data. The purpose of this note is to show that two of the missing members of the series can also be successfully correlated with the same interaction energies. PROPANOL-PROPYL ACETATEMeasurements of vapor-liquid equilibrium in n-propnnol-n-propyl acetate were reported independently in 1959 by Smirnova ( 4 ) and Pick et al. ( 5 ) . The two sets of data a,re in close agreement over the full concentration range. With the same values for interaction energies as were used by Sweeney and Rose, the vapor-liquid equilibrium data for this system at 760 mm. Hg were calculated.